摘要
LaB6-ZrB2 eutectic in situ composites are interesting candidates for manufacture of turbine blades because of their excellent mechanical properties. The oxidation behavior of LaB6-ZrB2 eutectic in situ composites prepared by electric are melting was studied in a temperature range of 916-1223°C and in a pressure range of 1.5 × 104-7.2 × 104 Pa. The specific weight change of the LaB6-ZrB2 eutectic obeys the Arrhenius equation below the oxidation temperature of 1094°C and appears to obey a paralinear equation above this temperature. The rate of weight change is described by kp = 9.71 × 10-3 exp(-31000/RT) mg2/cm4 min in the range 916-1094°C. Above 1094°C, rapid oxidation kinetics were observed, La2O3·B2O3 and La2O3·3B2O3 being the primary scale constituent with ZrO2 deficiency in the outer scale. The oxidation increases with PO(2) up to 3.9 × 104 Pa, above which the trend is reversed due to the active oxidation of ZrB2. The oxidation appears to be controlled by oxygen diffusion through the scale and the oxidized layers consist mainly of La2O3·B2O3, La2O3·3B2O3 and trace of ZrO2.
源语言 | 英语 |
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页(从-至) | 1945-1952 |
页数 | 8 |
期刊 | Acta Materialia |
卷 | 47 |
期 | 6 |
DOI | |
出版状态 | 已出版 - 23 4月 1999 |